Energy Use and Improvements to Cotton Production

For an economic activity input of 25 billion dollars1, the United States uses 760,000 TJ of energy on cotton farming2. Extrapolating from the fact that the United States produces roughly 16 percent of the world’s cotton3 and assuming relatively similar global farming practices, we can conclude that the United States figure represents roughly 1/6 of the total energy used in cotton production. This puts the global energy use for cotton production at nearly 4,500,000 TJ. While there certainly are small changes that could be made to increase efficiency and slightly lower the energy use, I’d like to take a look at another figure to put 4,500,000 TJ into perspective.

In order to put this number in a more familiar context, I’ll compare it to the aluminum industry, which we’ve been studying as one of the largest energy consumers. Although the textbook has some data for energy use in aluminum production, I opted to perform a calculation using the same method in which I calculated cottons energy use, so that the numbers would be comparable. For an economic activity input of 152 billion dollars4, the United States uses 7,450,000 TJ of energy2. This number only accounts for the energy used in primary production, and it’s an order of magnitude greater than the energy used in cotton production in the United States. An important concept discussed in the textbook is that of scale5. I think that cotton production has a small enough impact compared to other industries that increasing the efficiency would do little to decrease total energy consumption.

Although making cotton production more efficient would have little effect on overall energy consumption, there are a couple of small changes that could be done to slightly decrease energy use. Cotton recycling is difficult because breaking down fabric results in shorter fibers than the original cotton production, and those fibers are difficult to spin into new products. Also, the energy associated with transporting, sorting, breaking down and re-dying cotton can be very large.6 However, consumers can decrease their cotton demand by reusing cotton; rather than buying new clothes, buy secondhand; rather than buying hand towels or cleaning rags, use old shirts.

A primary area of concern with cotton production is the use of pesticides and fertilizers. While cotton may not be a huge contributor in terms of energy, it accounts for 25 percent of the chemical pesticides used in the United States7, and probably even more in under regulated parts of the world. While energy production releases a lot of greenhouse gases, I think that the unknown effects of pesticides and fertilizers could be much more damaging in the long run than the carbon releases associated with energy use. Below is a graph showing the amount of toxic releases from cotton farming in the United States:

Screen Shot 2016-03-28 at 2.05.31 PM

While ‘organic chemical manufacturing’ sounds benign, it actually includes many pesticides that can wreak havoc on local ecosystems and lead to the development of superweeds and other pests that pose a serious threat to future agriculture. Although it would be less energy efficient (which kind of goes against the topic of this post), I think that the cotton industry should start to switch over to bamboo or organic cotton.




Energy Use and Improvements to Cotton Production

5 thoughts on “Energy Use and Improvements to Cotton Production

  1. arabellas_helter_skelter says:

    Overall, this is a well-researched and thought-out post. Your pie chart was a useful supplement to the text. You mentioned that the US produces 16% of the world’s cotton. Given the large demand for cotton clothing in the world, I would imagine that cotton production would still be a large industry in the US, yet you say it is small. How small is it relative to other industries, or the overall GDP?
    You also suggested a switch to bamboo or organic cotton. Given that they’re also plant-based sources, how much more efficient would mass production of those crops be, compared to our current model of cotton? The organic cotton, for example. is still cotton; would a switch to organic be that much more energy efficient, given that planting and harvesting methods are probably still going to be the same.
    Also, I’m curious as to where Wikipedia got that number you provided in the first sentence.


  2. I really like the use of context in describing the energy requirements for cotton farming. The numbers generated at this scale(i.e. Terra joules) simply are not very understandable on their own. Contrasting the energy requirements of cotton farming with that of aluminum production was a clever way to show how these types of industrial processes fit together. Moreover, it gives some insight into where regulations can have the most impact. I also liked that you highlighted some of the second order effects that occur as a result of farming such as pesticide use and the associated cost to environment. Overall I wonder if cotton production at the modern industrial scales we have today can even be made more efficient or environmentally friendly. Usually in a commodity business such as cotton farming the margins are already quite low and any further regulation might make the whole business unprofitable.


  3. It seems from your research that a lot of the energy is due to the method of farming. While I agree that the reduction of pesticides due to organic farming would make a significant impact, I wonder however, how much that would increase the impact due to the reduced efficiency in the growing of cotton. If there were a way to more efficiently farm cotton without pesticides, It seems that that would be the best approach. I have heard of advances in indoor farming, which might eventually be applicable to cotton, and not just lettuce.


  4. I also really liked how you compared the energy use to that of aluminum, it really put the whole thing into perspective for me. I also find it interesting, if not surprising, where the energy use for cotton comes from. Whereas other materials may have huge mining energy “costs” or large energy use due to fabrication, cotton has energy use mostly from farming processes. This is interesting as it seems to make increasing energy costs slightly more convoluted. As always, great blog!


  5. It is interesting that you mention bamboo because I have previously read some articles about the renewability of bamboo and its advantages and disadvantages for use in textiles. The bamboo plant is nice because it can be considered as a grass because is grows fast and indefinitely. So environmentally bamboo is a great material, but why aren’t we using it. An interesting issue I’ve found is that bamboo doesn’t block UV as well as other materials. So if we were wearing clothing made out of bamboo fibers, we could still get sunburn. I imagine that with organic cotton, the production or yield of cotton is lower so less cost efficient as normal cotton production. Cotton growers aren’t going to switch over to organic methods because it will drive up prices for everybody, including consumers who will not be happy with that. Even if is is regulated nationally, people will just buy cheaper cotton from other countries. While it would be great to switch over to bamboo or organic cotton, because it is such a commodity, the cost is so important that even marginally more expensive options will have a hard time taking over.


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